diet pepsiNearly a year ago in Neither Reason nor Science Supports Class Actions against Diet Soda Makers, we applauded the dismissal of several copycat class-action lawsuits alleging that because the word “diet” in “diet soda” implies the beverage aids in weight loss, companies like Pepsi and Dr. Pepper were misleading consumers. Consumers were misled, the suits asserted, because the artificial sweetener being used causes weight gain. The plaintiffs cited scientific studies they said supported that conclusion.

One decision by the U.S. District Court for the Southern District of New York, Manuel v. Pepsi-Cola Co., thoroughly dismantled the studies plaintiffs relied upon, holding that at most the studies supported a correlation between the sweeteners and weight gain, not causation.

The U.S. Court of Appeals for the Second Circuit affirmed that decision last month. On April 17, the same court, in a curt summary order, affirmed the dismissal of another diet-soda suit by the Southern District of New York, Excevarria v. Dr. Pepper Snapple Group, Inc.  The order explained that even if the reasonable consumer believed that a product containing the word “diet” was making promises about weight management, the studies Excevarria cited did not establish a causal connection between the artificial aspertame and weight gain.

Several other dismissed diet-soda class actions are awaiting decisions from the Ninth Circuit. Because all these suits rely on the same flawed studies, Manuel and Excevarria should seal the fate of those pending appeals.